Selector switch contact construction with deformable contact support plate means



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HAS A236 2" qg United States Patent "ice SELECTOR SWITCH CONTACTCONSTRUC- TION WITH DEFORMABLE CONTACT SUP- PORT PLATE MEANS Henry W.Wallace, Weston, Conn., assignor to General Electric Company, acorporation of New York Filed Mar. 19, 1962, Ser. No. 180,628 Claims.(Cl. 200-11) This invention relates to electrical switches and moreparticularly to a multiple position switch and the method ofmanufacturing such switch. Although not so limited, the switch isparticularly useful for controlling the operation of an electricallyreversible, multi-speed, shaded pole fan motor. Likewise, the method ofmanufacturing the switch may be employed in making many types ofswitches having a wide variety of applications.

In the manufacture of electric fans or similar appliances, the largevolume of production frequently involved and the highly competitivenature of the business dictates that each component be as inexpensive aspossible while yet providing the necessary reliability. As a means forreducing costs, it is extremely desirable that automation be employed inthe manufacture of the various components. In addition to the foregoingcriteria, certain components such as switches must meet various rigidsafety requirements including provision to preclude shorting in theevent of overheating.

Accordingly, it is the primary object of this invention to provide animproved electrical switch assembly and method of manufacturing suchassembly.

It is a further object of this invention to provide a multiple positionswitch which may be inexpensively mass produced.

Another object of this invention is to provide an improved multipleposition switch for a multi-speed shadedpole fan motor.

It is a further object of this invention to provide an energy storingswitch knob which provides quick and positively acting switch operation.

Briefly stated, this invention relates to an electrical switchcomprising a punched metal contact plate forming a plurality of contactelements interconnected by metallic bridges and a molded support whichhas projections adapted to fit within the space between the contactelements. The support is made of thermoplastic or similar material sothat the projections extending through the spaces between the contactelements may be deformed under heat and pressure after the support isassembled with the contact plate. The contact elements may then besevered or separated by removal of the metallic bridges, thus leavingthe contact elements in spaced, insulated relationship.

The contact plate and support assembly may be sandwiched between a casecomprising a thermosetting plastic base and clamping member which areadapted to independently position the contact elements. A rotor carryingone or more contact connector units cooperates with the clamping member,and the entire assembly is securely clamped together by means of asuitable cover. To rotate the rotor, a plastic knob is provided havingan integral tongue which is adapted to engage the rotor. The tongueserves as an energy storing member so that rotation of the knob providesa positive snap action. To secure the knob to the rotor, the knob may beprovided with integral resilient legs adapted to cooperate with therotor.

Further features, objects and advantages will become apparent withreference to the following drawings, in which:

FIG. 1 is a perspective view of a punched metal contact plate of theinvention;

3,214,536 Patented Oct. 26, 1965 FIG. 2 is a perspective view of amolded thermoplastic support adapted to be assembled to the contactplate of FIG. 1;

FIG. 3 is a perspective view of the contact plate of FIG. 1 and thesupport of FIG. 2 after the components have been assembled and securedtogether by deformation of the thermoplastic support;

FIG. 4 is a perspective view of the assembly of FIG. 3 after a punchingoperation has been performed by which metallic bridges have been removedfrom the contact plate to form a plurality of contact elements securedto the support;

FIG. 5 is a plan, partially sectional view of the entire switch assemblyof the invention;

FIG. 6 is a side elevation sectional view of the switch assembly;

FIG. 7 is an exploded perspective view showing the switch knob, cover,rotor, shading coil selector unit and selector arm unit;

FIG. 8 is an exploded perspective view of the switch clamping member,contact plate and support assembly, and base member; and

FIG. 9 is a schematic version of the switch of the invention shownconnected to an electrically reversible three-speed fan motor.

The particular switch assembly shown and described herein is a rotaryseven position switch, useful for example with reversible, multi-speed,electric fans to provide three speeds in each direction and an ofiposition. Referring first to FIG. 6, the entire switch assembly may beseen as comprising a base 10, a support plate and contact assembly 12, aclamping and indexing member 14, a rotor 16 carrying a selector arm unit18 and a shading coil arm unit 20, a cover 22 and a knob 24. Thesevarious components will be individually described in detail in thefollowing paragraphs.

Describing first the support and contact assembly 12, there is shown inFIG. 1 a contact plate 26 having a pattern of apertures and forming aplurality of contact elements 28, 30, 32, 34, 36, 38 and 40 each havinga respective terminal 28a, 30a, 32a, 34a, 36a, 38a and 40a. Contactelement 36 is also provided with an additional terminal 36b. In FIG. 1,the contacts are interconnected by ten metallic bridges 42-51, which areto be removed in a subsequent operation. The contact plate with thebridges removed may be seen in FIG. 4 wherein the spaces formerlyoccupied by the bridges have been numbered identically with the bridges.

Since the bridges 42-51 are to be removed, it is necessary to providemeans by which the respective contact elements will be permanentlypositioned in the desired spaced, insulated relationship. For thispurpose, a support is provided having, as may be seen from FIG. 2, apattern of projections adapted to be received within a portion of thepattern of apertures formed in contact plate 26. The support 60 is alsoformed with a pattern of apertures which coincide with the remainingopen aperture portions of plate 26 for positioning the support and platewithin the switch base 10. In accordance with the invention, the support60 is preferably made of thermoplastic or similar material having theproperties of being deformable by heat and pressure and at the same timebeing a good electrical insulator. As the next step of the fabrication,the contact plate 26 is assembled with the support plate 60 so that theextensions or projections on the support extend through the apertureswithin the contact plate. It may be noted that both contact plate 26 andthe plastic support 60 are asymmetrical, so that they may be assembledonly in the proper manner. Next, certain projections are deformed byheat and pressure to thereby secure the contact plate to the support, asshown in FIG. 3. It should be noted that projections 62, 64, and foursemicylindrical projections, all indicated by the numeral 65, are notdeformed during the heat and pressure operation in that they serve asbearing surfaces in the operation of the switch. Also, a centrallylocated recess or socket 66 in the support 60 is not deformed in that itis' a bearing surface adapted to receive a portion of the rotor 16, aswill be hereinafter described.

After the deforming opeartion, the bridges 42-51 are removed in apunching operation or some other suitable method, leaving the spaces42-51 as shown in FIG. 4. By this operation, the contact plate 26 isseparated into seven different contact elements 28, 30, 32, 34, 36, 38and 40, which are supported in insulated relationship by the supportplate 60. It should be noted that portions of the thermoplastic support60 are also removed during the bridge removing operation as exemplifiedat spaces 43 and 51 in FIG. 4.

Although the contact and support assembly 12 may be produced by means ofthe manufacturing methods desired, one of the features of the assemblyis that it easily lends itself to automation mechanism. For example, theoperation may begin by passing a metal strip beneath punching equipmentto punch the pattern of apertures to form the contactplate 26; and bysuccessively repeating this operation, a strip of contact platesconnected by means of their terminals may be produced. While still instrip form, a support 60 may be assembled to each contact plate, thedeformation operation may be performed, and the bridges may be removedby a suitable punching operation. At this point, the contact plates arestill connected by their terminals; and it should be noted that althoughthere may be a small amount of play between the support and the contact,contact element 36 provides the necessary rigidity to the strip forfurther automatic procedures if desired in that both terminals 36a and36b would be connected to the adjacent contact plates. This continuousmetal strip also prevents sheer stresses from developing between themetal and the thermoplastic. The remainder of the switches may then beassembled on the strip before the contact plates are severed from oneanother. Of course, the contact plate 26 may be severed from the stripprior to the subsequent forming or punching operations it a lesserdegree of automation is preferred.

The support and contact assembly 12 is also shown in FIG. 8 where it isin position to be assembled to the base 10, which is provided with aplurality of upstanding projections adapted to fit within the spaces inthe assembly 12. Additionally, the base 10 is provided with a centralaperture 68 adapted to receive the base of socket 66-of the support 60.The base 10 also forms a major portion of the switch exterior as may beseen from the assembly drawing of FIG. 6. Again it may be noted thatbase 10 has its series of projections arranged asymmetrically, so thatcontact assembly 12 mates with the base only when assembled in aproperly oriented position.

After the contact and support assembly 12 has been placed'in the base10, the clamping member 14 is also received within the base over theassembly 12 to thereby sandwich the contact and support assembly betweenthe two members. The clamping member 14 is provided with recesses andprojections, some of which are shown at 72 and 74, adapted to mate withupstanding projections and recesses respectively of the base 10 toposition the contact and support assembly. In its preferred form thebase 10 and clamping member 14 are made of a heat resistant,non-conducting, thermosetting plastic, such as phenolic. With thisarrangement safety standards may be easily met. In the event the switchis overheated and the thermoplastic support 60 should melt or bedeformed, the contact elements will still be independently clamped ininsulated relationship by the base and clamping member so that theswitch will continue to function properly.

An asymmetrical design of clamping member 14 is again useful inconnecting with automatic assembly techniques.

It should be noted that the clamping member 14 is provided with openings76 and 78 through which the depending wiper arms of the selector armunit 18 and the shading coil arm unit 20 will extend, as shown in FIG.6. The clamping member 14 is also provided with a central opening 79surrounded by an upstanding annular ridge having radially extendinggrooves 80. The grooves 80 cooperate with the rotor 16 to provide thenecessary indexing action requiredof a snap action switch as well as thephasing, as will hereinafter be described.

The remaining elements of the switch assembly may be seen in theexploded perspective view of FIG. 7. The rotor or core 16, selector armunit 18 and shadingcoil arm unit 20 are adapted to be assembled as aunit and cooperate with the clamping member 14 and the contact andsupport assembly 12 to provide the contact connecting operation of theswitch. The rotor 16, which is made of a thermosetting plastic or otherelectrically insulating material, which will remain rigid whenoverheated, is provided with a shaft 82 having a rounded end which, aspreviously mentioned, is adapted to fit through the open ing 79 inclamping member 14 and be received in socket bearing 66 of support 60.

The two arm units 18 and 20 are made of suitable resilient electricalconducting material such as Phosphor bronze. The arm units are eachprovided with a central opening and are adapted to be press fitted overthe rounded shaft end 82, or the units may be secured to the rotor byother suitable means. As shown, the attached end of the rotor shaft isprovided with a pair of diametrically spaced flutes one of which isshown at 84. The flutes are adapted to receive the inwardly extendingtongues 86 of shading coil arm unit 20. By properly selecting thedimensions of the flutes and tongues the arm unit may be self-locking onthe shaft of rotor 16. The arm unit 20 is further provided with a pairof spring-like extremities 87 which are designed to snap-over thearrowlike extremity 88 on the rotor periphery to thereby lock the armunit in position, and proper orientation is assured. As may be seen fromthe drawing in FIG. 7, arm unit 20 is provided with a pair of flexible,depending wiper arms 90 and 92 which are adapted to extend throughopening 76 in clamping member 14 to cooperate with the contact elementsof the switch, as will be hereinafter described. When assembled, thepressure of the contact arms 90 and 92 against the switch contactelements assists in maintaining the arm unit 20 in engagement with therotor 16.

After the arm unit 20 has been secured to the rotor 16, the selector armunit 18 may be pressed onto the shaft 82 of the rotor and securedthereto, in a manner similar to arm unit 20, by a pair of inwardlyextending tongues 94 frictionally engaging a second pair of flutes oneof which is shown at 96 on the shaft 82. A pair of wiper arms 98 and 100diametrically aligned with wiper arms 90 and 92, depend from the armunit 18 and are adapted to extend through the openings 76 and 78,respectively, in the clamping member 14 to engage the switch contactelements, as will be hereinafter described. When the switch isassembled, the wiper arms 98 and 100 are pressed into engagement withthe contact and support assembly 12. This assists in maintaining the armunit 18 on the shaft 82. The arm unit 18 is also provided with a pair ofradially extending corrugated sections 102 and 104 which are adapted tomate'with the radial grooves 80 in the clamping member 14. Thecorrugated sections 102 and 104 and grooves 80 serve as detent means toresist rotation of the rotor. They assist also in maintaining the armunit 18 on the shaft 82. Four wing-like extremities on the unit 18, twoof which are shown at 106 and 108 cooperate with four, peripheral,step-like features 110, 112, 114 and 116 located on the periphery ofrotor 16. The flanges of the four wing-like extremities in contact withthe step-like features of the rotor transmit torque between the selectorarm unit and the rotor. The step-like features 110 and 112 also resultin a cut-away clearance area necessary for the flexing of the corrugatedsection 102 with respect to the areas 106, 108 and that area of arm unit18 which bears against the shaft 82 of the rotor 16. This applies alsoto steplike features 114 and 116.

Once the rotor with its accompanying wiper arm units have been assembledwith the clamping member 14, contact and support assembly 12 and base10, the entire assembly should be secured together to maintain theproper relation between the respective components. For this purpose, thecover 22 having an upstanding tubular neck 132 fits over the core orrotor 16 and abuts the combined upper peripheral flange of clampingmember 14 and base 10. Although it may not be completely clear from thedrawings, the upper tubular neck 134 of core 16 is formed with a slighttaper from a larger diameter adjacent flange 134a to a smaller diameterat the upper edge 134b, as viewed in FIGS. 6 and 7. This facilitates themolding operation. The inner surface of the neck 132 of cover 22 isformed with a cylindrical zone 132a at the base of the neck followed bya major tapered section 1321) of greater taper than the taper of coreneck 134, and terminating with another cylindrical zone 1320 at the topof the neck. The resulting ring contact between core neck 134 and zones132a and 132C of cover neck 132 provide double bearing assembly foraligning the rotating core 16 within the cover 22. The cover 22 may besecured in the assembled position by means of a pair of dependingintegral tabs 118 and 120, which may be inwardly deformed into a pair ofrecesses 122 and 124 formed in the outer wall of the base and deformedagainst the respective upper walls of the recesses, as seen in FIGS. 6and 8. The depending cover lugs 126, 128 and 130, along with the tabs118 and 120, position the cover 22 with respect to the clamping member14 and base 10, as best seen in FIG. 5.

For proper operation of the switch it is necessary to provide a means bywhich the rotor 16 may be rotated to the various switch positions. Forthis purpose, there is provided the energy storing snap-acting knob 24preferably made of polypropylene or similar material. In accordance withthe invention, as seen in FIGS. 5, 6 and 7, the knob is formed with anintegral tongue or reed 136, which is adapted to be inserted through theupper opening in rotor 16 into a slot 138 within the rotor which istapered so that the body of the plastic tongue or reed will haveclearance for torsional strain while its top remains securely engaged inthe bottom of the tapered slot. To secure the knob 24 to the rotor 16,the knob is provided with a pair of downwardly extending diametricallyspaced legs 140 and 142 each having an outwardly extending nib 144 and146 respectively. Each nib may be formed with an arcuate periphery so asto conform to the curvature of the recesses 148 and 150 within the innerwall of the rotor. The rotational angular freedom existing between thearc extremities of the nibs 144 and 146 and their respective recesses148 and 150 establishes the limits of energy storage required forproviding snap action to the switch.

The dimension between the outer edges of the nibs is larger than thediameter of the opening within the rotor so that in order to assemblethe knob to the rotor, the knob legs are pressed toward each other andinserted into the rotor. When the nibs are aligned with the recesses,the resiliency of the legs snaps the nibs into the respective recessesto thus secure the knob. The recesses 148 and 150 may be provided with aperipheral dimension slightly larger than the peripheral dimension ofthe nibs 144 and 146 to limit the rotational movement of the knob withrespect to the rotor. For example, the leg nibs 144 and 146 might have a30 angular dimension and the recesses have 48, to allow the knob angularfreedom of plus or minus 9.

In operation, rotation of the knob 24 will cause the tongue or reed 136to engage the side walls of slot 138 causing the tongue to twist as theknob is further rotated. When the torque thereby applied to the rotor issufficient to overcome the restraining force between the radiallyextending corrugations 102 and 104 and the mating radially extendinggrooves in the clamping member 14, the wiper arms extending from the armunits 18 and 20 will be rotated with a snap action. During the relativerotation between the knob 24 and the rotor 16, the upper surface of thecylindrical portion of the rotor abuts the lower planar surface of theknob. The upper portions of the legs 140 and 142 may be radiallyenlarged to engage the inner wall of the rotor to form an additionalbearing surface.

The limits of rotation of the energy storing plastic knob 24 withrespect to the switch proper are determined by the two dependingreinforced knob ribs 152 and 154 alternately engaging the upturned tang156 of the mounting cover 22, as shown in FIG. 7. If only a portion ofthe switch contacts are to be employed, the rotation of the knob 24 maybe further limited by providing an additional upstanding tang on thecover 22 spaced at the desired location. By so modifying the cover 22,the switch may be employed in different electrical units thus providingversatility to keep manufacturing costs to a minimum.

As mentioned before, the switch described herein may be employed indiiferent types of electrical equipment, but the particular embodimentdescribed is adapted to control the operation of a three-speedelectrically reversible shaded pole fan motor. To complete theunderstanding of the operation of the switch, a brief description of itsfunction when used with such a motor will be given. Referring to FIG. 9,there is shown a schematic drawing of the contact support assembly 12and the selector arm units 18 and 20 connected to a shadded pole motorshown schematically as including a pair of serially connected shadingcoils 162 and 164 and three serially connected primary motor coils 166,168 and 170 to provide high, medium and low speed operation.

As may be seen from FIG. 9, one end of shading coil 162 is connected tocontact 30 of the contact assembly, while one end of shading coil 164 isconnected to contact 28. The shading coil circuit is completed byconnecting a center tap between the two shading coils to contact 34. Thewiper arms 90 and 92 of the shading coil arm unit 20, as seen in FIGS. 6and 9 are positioned to cooperate with contacts 28, 30 and 34 as the armunit 20 is rotated. With the wiper arms 90 and 92 positioned as shown inFIG. 6, the switch is in the oif position wherein wiper arm 92 isengaged with contact 34 while wiper arm 90 engages the plasticprojection 62 so that the shading coil circuit is open. Wiper arm 92engages contact 34 at all times; and by rotating the knob and rotaryassembly in one direction wiper arm 90 will engage contact 28 to closethe shading coil circuit to shade motor rotation in one direction. Byrotating the arm unit 20 in the opposite direction, wiper arm 90 willengage contact 30, as shown in FIG. 9, to again close the shading coilcircuit, but to shade motor rotation in the opposite direction.

As may be seen from FIG. 9, one lead' 174 to be connected to a linepower supply is connected to one end of primary coil 166, and the otherlead 176 is to be connected to contact 32 of the terminal assembly 12.The various motor speeds may be obtained by selectively connecting theprimary motor coils, by means of the switch of the invention, to thepair of line terminals 174 and 176. More specifically, the end ofprimary motor coil 166, remote from the line terminal, is connected tocontact 36; the end of coil 168 adjoining coil 170 is connected tocontact 38; and the opposite end of coil 170 is connected tocontact.40.. Wiper arms 98 and 100 of selector arm unit 18 representedby the tips of arm unit 18 in FIG. 9, cooperate with the switch contactsto determine which coils will be included in the circuit to obtain thedesired motor speed. More specifically, wiper arm 98 continuouslyengages contact 32 while wiper arm 100 selectively engages the contacts36, 38 and 40, one of the projections 65, or the plastic projection 64.When the switch is in the off position as shown in FIG. 6, wiper arm 100engages plastic projection 64 so that the primary motor coil circuit isopen. As the switch selector knob 24 is rotated in either direction,wiper arm 98 continues to engage contact 32, connected to power lineterminal 176, while, wiper arm 100 initially engages contact 40. In thisposition, the current passes through all three motor coils in series toobtain low speed operation.

It should be understood that the arm units 18 and 20' are insulated fromeach other and rotate together as the knob 24, FIG. 6, is rotated. Byrotating the knob 24 from the off position, towards the low speedposition, wiper arm 90 engages either contact 28 or 30, depending uponthe direction of rotation, to close the shading coil circuit beforewiper arm 100 engages contact 40 to close the circuit connecting theprimary motor coils. Con versely, when the know is turned from an on toan ofi position, the primary motor coil circuit is broken before theshading coil circuit is broken. By this arrangement, undesirable surgecurrents are eliminated which might occure if the circuits wereconnected and disconnected in the reverse order.

As the switch is further rotated, the wiper arm 100 is forced over aprojection 65 to engage contact 38 so that the current will then flowthrough coils 166 and 168 to obtain medium speed operation. Furtherrotation of the selector knob 24 will cause the wiper arm 100 to beforced over a projection 65 to engage contact 36 as shown in FIG. 9; andsince wiper arm 98 continues to engage contact 32, the current will flowonly through primary coil 166 to obtain high speed operation. Theprojections 65 contribute to the indexing action of the switch as wellas to more rapidly extinguish arcing due to the lifting of the arm 100caused by the projections. Along these lines, it should also be notedthat the contacts 36, 38 and 40 are each provided with a raised detent158, FIG. 4, on each side of the plastic projection 64 in the arctravelled by the tip of wiper arm 100. The detents prevent slippage ofwiper arm 100 and require positive action, to move the wiper arm 100.Thus, it will be appreciated that three-speed motor operation in twodirections is obtained by connecting the switch assembly of the inrvention in the manner heretofore described.

The particular embodiment described herein is, of course, merely anexample of the invention, and it will be obvious to those skilled in theart that various changes and modifications may be made without departingfrom the invention in its broader aspects. For example, the plasticprojections 65 formed on the thermoplastic support plate 60 and theportion of projection 64 positioned in the path of the tip of wiper arm100 may be eliminated from the plate 60 and replaced by aperturesthrough which comparable projections formed on the thermosetting basecould extend. The projections on the base 10 could serve the samefunction as the projections 64 and 65; but being made of thermosettingmaterial, they would not be deformed in the event of overheating.Further, as previously explained, the invention is not limited toswitches for electric fans. The contact and support assembly and themethod of manufacturing may be employed in fabricating many differenttypes of switches. Likewise, the energy-storing knob may find usefulapplication in a variety of switches and other devices. Therefore, it isintended in the appended claims to cover all such changes andmodifications which fall within the true spirit and scope of thisinvention.

Having thus described the invention, what is claimed is;

1. In a multiple position electrical switch,

(a) a thermoplastic support plate having a plurality of projectionsextending from one surface of the plate;

(b) a plurality of switch contact elements arranged in spaced relationin a single plane between said projections and held in such position bythe plate;

to) an enclosing case made of thermosetting plastic material surroundingsaid contact elements and said support plate and including a pluralityof projections to position the contact elements in spaced insulatedrelation independently of said support plate; and

(d) movable contact means supported by said case for varying theelectrical circuits through said switch contact elements.

2. The switch of claim 1 in which some of the projections of saidsupport plate are positioned to engage and separate said contact meansfrom said contact elements as the contact means are moved to theirvarious positions.

3. In a multiple position electric switch,

(a) a plurality of switch contact elements arranged in spaced relationin a single plane;

\(b) a thermoplastic support plate having a plurality of projectionsextending from one surface of the plate, said plate being positioned inparallel relation to said contact elements with said projectionsextending between said contact elements to hold said contact elements ininsulated spaced relation to each other; 1

(c) means formed integral with the ends of said projections to securesaid contacts to the plate;

'(d) an enclosing case made of thermosetting plastic material supportingsaid contact elements and said support plate; and

(e) movable contact means supported by said case for cooperating withsaid contacts to vary the elec trical circuits through said switch.

4. A multiple position, snap-action, electrical switch comprising:

(a) a plurality of contact elements;

(b) a thermoplastic support positioning said contact elements in spacedinsulated relationship;

(c) a thermosetting plastic base and clamping member holding saidsupport and said assembled contact elements therebetween, said base andclamping member being made of material capable of withstandingtemperatures substantially higher than said thermoplastic support sothat the contact elements will remain in insulated relation even thoughthe support is deformed by excessive heat;

(d) a rotary member extending through an opening in said clamping memberto selectively connect said contact elements; and

(e) a plastic knob for rotating said rotary member and including anintegral tongue engageable with the rotor and formed to provide energystorage means whereby the rotor is moved with a snap action.

5. The switch of claim 4 wherein said knob is formed with a pair of legspositioned on opposite sides of said tongue and extending in thedirection of said tongue, each of said legs having an outwardlyextending nib, means defining a pair of arcuate recesses within saidrotary member, said legs being positioned within said rotary member witheach of said nibs being positioned within a r e spective one of saidrecesses to limit the rotational movement of said knob with respect tothe rotary member and hence the energy which may be stored by the knob.

6. A multiple position, snap-action, electrical switch comprising:

(a) a plurality of contact elements:

(b) a thermoplastic support positioning said contact elements in spacedinsulated relationship;

(c) a thermosetting plastic case enclosing said support and saidassembled contact elements;

(d) a rotary member extending through an opening in said clamping memberto selectively connect said contact elements; and

(e) a plastic knob for rotating said rotary member and including anintegral tongue engageable with the rotor and formed to provide energystorage means whereby the rotor is moved with a snap action.

7. A multiple position, snap-action, electrical switch comprising:

(a) a plurality of contact elements;

(b) a thermoplastic support positioning said contact elements in spacedinsulated relationship;

() a plastic base and clamping member holding said support and saidassembled contact elements therebetween, said base and clamping memberbeing made of material capable of withstanding temperaturessubstantially higher than said thermoplastic support so that the contactelements will remain in insulated relation even though the support isdeformed by excessive heat;

(d) a rotary member extending through an opening in said clamping memberto selectively connect said contact elements, said rotary member andsaid clamping member having mating detent means to restrain rotation ofthe rotor; and

(e) a plastic knob for selectively rotating said rotary member andincluding an integral tongue engageable with the rotor and formed toprovide energy storage means whereby said rotor is moved with a snapaction.

8. A multiple position, snap-action, electrical switch comprising:

(a) a plurality of contacts;

(b) means supporting said contacts in spaced insulated relation;

(0) a rotor supported by said supporting means and carrying contactmeans cooperating with said contacts for completing the various switchcircuits;

(d) a plastic knob selectively rotating said rotor including an integralplastic tongue engageable with the rotor to provide energy storage meanswhereby said rotor is moved with a snap action when said knob isrotated;

(e) a pair of diametrically spaced legs formed integral with said knoband extending on opposite sides of said tongue;

(f) means defining a pair of arcuate recesses within said rotor; and

(g) stop means formed integral with said legs extending into saidrecesses to limit the rotational movement of the knob relative to therotor and to thereby limit the rotational energy which may be stored bysaid knob to obtain the switch snap action.

9. A multiple position action switch comprising,

(a) a plurality of contact elements,

(b) a thermoplastic support having integral deformed projectionssecuring said contact elements in spaced insulated relationship,

(c) a thermosetting plastic base receiving said support,

(d) a thermosetting plastic clamping member mating with said base tosecure said contact elements therebetween independently of saidthermoplastic support,

(e) a rotor received within an opening in said clamping member andhaving wiper arms extending through openings within the clamping memberto selectively connect said contact elements,

(f) said rotor and said clamping member having mating detent means torestrain rotation of the rotor, and

(g) a cover member for securing the rotor to said base and securing saidclamping member and said support therebetween.

10. A multiple position snap action electrical switch comprising,

(a) a plurality of contact elements,

(b) a thermoplastic support plate having a centrally located socket andincluding a plurality of deformed projections securing said contactelements in spaced insulated relationship surrounding said socket,

(c) an insulated base receiving said support carrying the contactelements,

(d) a clamping member to mate with said base to position the support andcontact elements therebetween,

(e) a rotor positioned within said insulated base and having a centralshaft extending through an opening within said clamping member to fitwithin the socket in said plastic support,

(f) selector means mounted on said shaft and having wiper arms extendingthrough openings within said clamping member to selectively connect saidcontact elements,

(g) said rotor and said clamping member having mating detent means torestrain rotation of the rotor, and

(h) a plastic knob including an integral tongue engageable with therotor to provide energy storage means whereby said rotor is caused tomove with a snap action as the knob is rotated.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS8/50 Great Britain.

OTHER REFERENCES German application, 1,084,804, July 1960.

60 BERNARD A. GILHEANY, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,214,536 October 26, 1965 Henry W. Wallace It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 9, line 56, for "action" read snap action Signed and sealed this27th day of September 1966.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER AttestingOfficer

1. IN A MULTIPLE POSITION ELECTRIC SWITCH, (A) A THERMOPLASTIC SUPPORT PLATE HAVING A PLURALITY OF PROJECTIONS EXTENDING FROM ONE SURFACE OF THE PLATE; (B) A PLURALITY OF SWITCH CONTACT ELEMENTS ARRANGED IN SPACED RELATION IN A SINGLE PLANE BETWEEN SAID PROJECTIONS AND HELD IN SUCH POSITION BY THE PLATE; (C) AN ENCLOSING CASE MADE OF THERMOSETTING PLASTIC MATERIAL SURROUNDING SAID CONTACT ELEMENTS AND SAID SUPPORT PLATE AND INCLUDING A PLURALITY OF PROJECTIONS TO POSITION THE CONTACT ELEMENTS IN SPACED INSULATED RELATION INDEPENDENTLY OF SAID SUPPORT PLATE; AND (D) MOVABLE CONTACT MEANS SUPPORTED BYY SAID SAID FOR VARYING THE ELECTRICAL CIRCUITS THROUGH SAID SWITCH CONTACT ELEMENTS. 